🎁 Free Diagrams: [ Ссылка ]
📖 My book on Amazon: [ Ссылка ]
MIDI: [ Ссылка ]
MEGA: [ Ссылка ]
MEGA 70V: [ Ссылка ]
ANL: [ Ссылка ]
MRBF: [ Ссылка ] + [ Ссылка ]
Class-T: [ Ссылка ]
NH00: Siemens, Bussmann, or Eaton
Imagine this: a short circuit happens, and your battery releases 4,000A of current. If your fuse isn’t up to the task, it won’t stop the flow—potentially leading to catastrophic damage or even a fire. Many people don’t realize their fuses aren’t properly rated until it’s too late.
Why Most Fuses Fail
A fuse isn’t just about matching the current rating to your system—it needs to handle worst-case scenarios like short circuits. That’s where two key specs come into play:
1️. Interrupt Current Capacity (ICC): The maximum short-circuit current the fuse can safely interrupt.
2. Voltage Rating: The system voltage the fuse is designed for.
Lithium batteries, with their low internal resistance, can deliver currents up to 10 times their capacity during a short circuit. For example, a 12V 300Ah lithium battery can produce up to 3,000A in a short—far beyond what many fuses can handle. If the fuse’s ICC is too low, it may fail, causing dangerous arcing or melted components instead of breaking the circuit.
Link to the study mentioned in the video:
[ Ссылка ]
Voltage rating matters too. A 32V-rated fuse won’t safely protect a 48V system and could fail dangerously. For 48V setups, always use fuses rated at 70V or higher.
Fuse Recommendations for Different Systems
Here’s how to choose the right fuse for your setup:
MIDI/AMI Fuses: Best for 12V and 24V systems up to 200Ah. These are compact and ideal for smaller systems.
MEGA/AMG Fuses: Suitable for 12V and 24V systems up to 250Ah. MEGA fuses also come in 70V versions, making them usable in 48V systems with up to 250Ah capacity.
MRBF Fuses: These mount directly to your battery terminals, reducing cable crimps. Perfect for 12V, 24V, and 48V systems up to 200Ah.
ANL Fuses: These larger fuses are suitable for 12V and 24V systems with capacities up to 600Ah. However, they’re not recommended for 48V systems due to their lower voltage ratings.
Class-T Fuses: Ideal for larger 48V systems. With ICC ratings of 20,000A and voltage ratings up to 125V, they work for batteries up to 2,000Ah.
NH00 Fuses: Commonly used in Europe, these can handle ICCs of 25,000A and are suitable for 48V batteries up to 2,500Ah.
Parallel Battery Systems
If you have parallel batteries, fuse each battery individually and add a main fuse to handle the combined short-circuit current. For example, with two 12V 200Ah batteries in parallel (producing 4,000A during a short), use MEGA fuses for each battery and a Class-T fuse for the main line.
Don’t Rely on Your BMS
Your Battery Management System (BMS) is designed for normal operation, not short-circuit protection. It can’t handle the massive currents produced in a fault. That’s why correctly sizing your fuses is critical for safety.
